How to limit the number of choices based on a value?

[studentlearner]

So I'm trying to limit the number of times each respective project can be repeated based on the table that starts on D18 (the no of available projects table), So this is how the table looks like at the moment:

ExcelAutomationSPT (1).xlsm
	A	B	C	D	E	F
1	Employee Name	Attendance Percentage	Choice1	Choice2	Choice3	FinalChoice
2	Alan	92	Project 1	Project 2	Project 3	Project 1
3	John	89.66666667	Project 2	Project 1	Project 3	Project 2
4	Aaron	85	Project 3	Project 2	Project 1	Project 3
5	Chris	84.33333333	Project 1	Project 2	Project 3	NIL
6	Tommy	81.66666667	Project 1	Project 3	Project 2	NIL
7	Jack	81.33333333	Project 1	Project 3	Project 2	NIL
8	Bob	75.09333333	Project 2	Project 1	Project 3	NIL
9	Ethan	73.15	Project 1	Project 3	Project 2	NIL
10	Fred	73	Project 2	Project 3	Project 1	NIL
11	Sam	60	Project 3	Project 1	Project 2	NIL
12	Ken	55	Project 1	Project 2	Project 3	NIL
13	Sasuke	52	Project 2	Project 3	Project 1	NIL
14
15
16
17			Project	No Of Available Position
18			Project 1	3
19			Project 2	4
20			Project 3	4
Final

Cell Formulas
Range	Formula
F2:F13	F2	=INDEX(FILTER(C2:E2,ISNA(MATCH(C2:E2,F$1:F1,0)),"NIL"),1)

And this is how it should look like at the end:
Do notice that the final choice limits itself based on the values at D18:D20, any help with formula or VBA would be great, Thank you!

ExcelAutomationSPT (1).xlsm
	A	B	C	D	E	F
1	Employee Name	Attendance Percentage	Choice1	Choice2	Choice3	FinalChoice
2	Alan	92	Project 1	Project 2	Project 3	Project 1
3	John	89.66666667	Project 2	Project 1	Project 3	Project 2
4	Aaron	85	Project 3	Project 2	Project 1	Project 3
5	Chris	84.33333333	Project 1	Project 2	Project 3	Project 1
6	Tommy	81.66666667	Project 1	Project 3	Project 2	Project 1
7	Jack	81.33333333	Project 1	Project 3	Project 2	Project 3
8	Bob	75.09333333	Project 2	Project 1	Project 3	Project 2
9	Ethan	73.15	Project 1	Project 3	Project 2	Project 3
10	Fred	73	Project 2	Project 3	Project 1	Project 2
11	Sam	60	Project 3	Project 1	Project 2	Project 3
12	Ken	55	Project 1	Project 2	Project 3	Project 2
13	Sasuke	52	Project 2	Project 3	Project 1	NIL
14
15
16
17			Project	No Of Available Position
18			Project 1	3
19			Project 2	4
20			Project 3	4
Final

Cell Formulas
Range	Formula
F2:F4,F13	F2	=INDEX(FILTER(C2:E2,ISNA(MATCH(C2:E2,F$1:F1,0)),"NIL"),1)

 

[Fluff]

A brute force approach.

=IF(COUNTIFS(F$1:F1,C2)<VLOOKUP(C2,$C$18:$D$20,2,0),C2,IF(COUNTIFS(F$1:F1,D2)<VLOOKUP(D2,$C$18:$D$20,2,0),D2,IF(COUNTIFS(F$1:F1,E2)<VLOOKUP(E2,$C$18:$D$20,2,0),E2,"Nil")))